Pressure-fluid motor



April 28, 1931. E. G. GARTIN PRESSURE FLUID MOTOR Original Filed June 4,1927 Patented Apr. 28, 1931 unrrsn STATES PATENT {OFFICE ELMER G.GARTIN, F CLAREMONT, NEW HAMPSHIRE, ASSIGNOR- TO SULLIVAN IMA- CHINERYCOMPANY, A CORPORATION OF MASSACHUSETTS PRESSURE-FLUID MOTOR Applicationfiled June 4, 1927, Serial No. 196,430.- Renewed. December 26, 1929.

This invention relates to pressure fluid motors and more particularly topressure fluid motors of the hammer type.

An object of this invention is to provide an improved pressure fluid.motor. A further object is to provide an improved pressure fluid motorof the hammer piston type wherein pressure fluid is suppliedcontinuously to the front pressure area on the hammer piston andsupplied periodically to the rear pressure area on the piston under thecontrol of an automatic piston-controlled fluid distribution valve. Afurther object is to provide an improved pressure fluid motor whereinthe fluid distribution means is extremely simplified and the power andefficiency of the motor is materially increased. These and other objectswill, however, hereinafter more fully appear.

In the accompanying drawing there is shown for purposes of illustrationone form which the invention may assume in practice.

In this drawing,

Fig. 1 is a central longitudinally extending 25 sectional viewillustrating the improved pres sure fluid motor.

Fig. 2 is an enlarged sectional view similar to Fig. 1 showing the valveand piston in different positions. a

as Fig. 3 is a transverse sectional view taken on line 33 of Fig. 1.

In this illustrative construction there is shown a pressure fluidmotor-of the hammer type comprising a cylinder 1 having abore 2 in whicha hammer piston 3 is reciprocably mounted. The hammer piston 3 hasformedintegral therewith and projecting forwardly therefrom a striking bar 4movably mounted in a bore 5 formed Within a front buffer ring 6. Asshown, the cylinder 1 is provided with a forwardly projectingsleeve-like portion 7 having a bore 8 in which the buffer ring 6 ispositioned. The rear end of the buffer ring 6 isseated against ashoulder 9 formed at the junction of the cylinder bore 2 and the bore 8,this buffer ring being held in position by a front chuck housing 10projecting within the bore 8 and abutting against the forward end of'the buffer ring. The chuck housing 10 carries at the forward combinedhead, block and valve chest 15 while engaging the outer surface of thishead block is arear plate 16. The chuck housing, buffer ring, cylinder,rear head block and rear plate are held in assembled relation in anysuitable and convenient manner.

In the improved construction the valve chest 15 has formed thereinalined bores 17 and 18 of difle-rent diameters and preferably havingtheir axes'alined with the longitudinal axis of the motor cylinder.Reciprocably mounted within the bores 17 and 18 is an automaticpiston-controlled fluid distribution valve 19, herein preferably of thethree spool differential type. The valve 19 is pro vided with a largerear end spool 20 fitting the bore l7and a central spool 21 and a frontend spool 22 bothfitting the bore 18. As K shown, the spools 20, 21 and22 are connected by reduced portions 23 and 24. The outer end of thebore 17 is closed by the rear plate 16. Formed in the valve chest 15 atthe forward end of the bore 17 and at the rear end of the bore 18respectively are annular grooves or recesses 25 and 26, while locatedintermediate these grooves is a similar groove 27. Fluid pressure isadapted to be supplied to the motor through a longitudinal passage 28communicating at 29 withthe cylinder bore 2 at the forward end thereof.

eating with the cylinder bore 2 intermediate the ends thereof as by aport 32 is a longitudinally extending throwing passage 33 whichcommunicates with the bore 17 adjacent the rear end thereof. Extendingcentrally through the valve 19 and communicating with the bore 17 is arestricted leak passage 34: which in turn communicates through -alateral port 35 with the bore 18 at a point intermediate thespools 21and In the operation of the improved pressure fluid motor it will beassumed that the hammer piston 3 is in the position shown in Fig. l andis about to be driven forwardly to effect its working stroke. At thistime, pressure fl'ui'd flows from the passage 28 through the lateralpassage 29 into the annular recess 25, through the bore 18, the annularrecess 2'7 and thence through the passages 31 to the rear end of thecylinder b'ore Simultaneously, pressure fluid flows through the supplypassage 28 through the lateral port 29 to the fo rw'arden'd 'of thecylinder bore, the fluid flowing from the forward end 'of the cylinderbore through the port 32 and throwing passage 33 to the bore 17, and asa result the valve 1 9 is held in its forward position shown in Fig. .1.Due to the rel'ativelylarger pressure area on the rear surface of thehammer piston the pressure acting on the relatively small front pressurearea-of the piston is overcome and consequently the hammer piston isdriven forwardly. During this forward stroke of the piston the port32 iscut o l"? by the piston head and the pressure within the bore 17 at therear end of the valve leaks out through the passage 84, port 35,through. the radial exhaust passages directly to atmosphere. Continuouspressure acting on the forward surface of the relatively large spool 20causes the valve to be thrown rearwardly to the position shown in Fig.The pistoncontinues its forward travel due to the expansive action ofthe pressure fluid and momentum and delivers a blow to the shank of thedrill steel 12. \Vhen the valve assumes the position shown in Fig. 2 thepressure fluid in the rear end of the cylinder bore is exhausted toatmosphere through the passages 31, annular recess '27, through the bore18, annular recess 26 and passages -30 to atmosphere. The hammer pistonis then driven rearwa rdly by the pressure fluid within the forward endof the cylinder bore acting continuously on the forward pressure area ofthe hammer piston. As the piston 3 moves rearwardly thoport is againuncovered and pressure fluid is admitted through the throwing passage 35and the valve is again thrown forwardly to'the position shown in Fig. 1and thiscycle of operation is repeated throughout the normal operationof the motor. v H

As a result of tl "s invention an improved pressure fluid motorisp'rovided wherein the pressure fluid acts continuously on the forwardpressure area of the piston while the pressure fluid is periodicallysupplied to act on the relatively large pressure area on the pistonunder the control of an automatic pis ton controlled valve. It Willfurther be noted that an improved pressure fluid motor is providedwherein the fluid distribution means is exceedingly simplified andwherein the power and efficiency of the motor is materially increased.These and other advantages of this invention will be clearly apparent tothose skilled in this art.

Vhile I have in this application specifically described one form whichmy invention may assume in practice, it will be understood that thisform of the same is shown for purposes of illustration and that theinvention may be modified and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. A pressure fluid motor comprising a cylinder, a. piston reciprocabletherein, and fluid distribution means for effecting reciprocation ofsaid piston including a passage for constantly admitting pressure fluidto the front end of said piston, means for controlling the supply andexhaust of fluid for the rear end of said piston comprising areciprocable differential fluid distributon valve having a large spooland a reduced spool, a pas sage controlled by said piston for admittingpressure fluid from said cylinder to one surface of said large spool forthrowing said valve in one direction to connect the rear end of saidpiston through the valve chest directly with the rear end of said firstmentioned passage, and a passage for constantly admitting pressure fluidto the opposite surface of said large spool to throw said valve in theopposite direction to connect the rear end or said piston with theexhaust.

2. A pressure fluid motor comprising a cylinder. a piston reciprocabletherein, and fluid distribution means for effecting reciprocation ofsaid piston including means for constantly admitting pressure fluid tothe front end of said piston,'means for control ling the supply andexhaust of fluid for the rear end of said piston comprising areciprocable difl'erential fluid distribution valve having a large spooland a reduced spool. a passage controlled by said piston for admittingpressure fluidfrom said cylinder to one surface of said large spool forthrowing said valve in one direction to connect the rear end of saidpiston with'the fluid supply, a passage for constantly admittingpressure fluid to the opposite surface of said large spool to throw saidvalve in the opposite direction to connect the rear end 'ofsai-d pistonwith the exhaust. and a leak passage formed in said valve forc'oii'necting the pressure area at the Ill) rear end of said large spoolcontinuously with the exhaust. Y

3. A pressure fluid motor comprising a surface of said large spool forthrowing said valve in one direction, supply and exhaust passagescontrolled by said central spool, and means for constantly admittingpressure fluid to the opposite surface of said large spool for throwingthe valve in the opposite direction.

4. In a drilling apparatus, a pressure fluid actuated percussive motor,a piston reciprocable therein, a striking bar projecting from the pistonthrough one end of the cylinder,

and fluid distribution means for actuating said pistonincluding meansfor continuously admitting fluid pressure to the forward end of thecylinder to act on thereduced area of the piston around the strikingbar, a valve for controlling the supply and exhaust of fluid to and fromthe rear end of the cylinder,

said valve having a reduced spool for controlling the communicationbetween the cylinder and the supply and exhaust, said valve also havinga larger spool presenting an unbalanced area continuously subjected tofluid actuated percussive motor having a cyllnder, a piston headreciprocable therein, a striking supply pressure'tending to hold thevalve in position for opening the rear end of the cylinder to exhaustand means controlled by the piston for intermittently throwing the valveto its other position for admitting pressure fluid to the rear end ofthe cylinder.

5. In a drilling apparatus, a pressure flllld actuated percussive motor,a piston reciprocable therein, a striking bar projecting from the pistonthrough one end of the cylinder, and fluid distribution meansforactuating said piston including means for continuously admittingfluid pressure to the forward end of the cylinder to act on the reducedarea of the piston around the striking bar, a valve for controlling thesupply and exhaust of fluid from the rear end of the cylinder, saidvalve having a central spool for alternately establishing communicationof the rear end of the cylinder with the supply and exhaust, a

larger spool on one side of said central spool,

said spools having adjacent opposed surfaces presenting a differentialarea to the action of fluid supply pressure tending to hold the valve inone extreme position for openlng the rear end of the cylinder toexhaust, and a throwing passage controlled by the piston for admittingpressure fluid from the cylinder to the opposite side of said largerspool for throwing the valve to its other extreme posi tion foreflectingadmission to the rear end of the cylinder, and guiding means on saidvalve on the opposite side of said central spool from the larger spool.

6. In a drilling apparatus, a pressure fluid actuated percussive motor,a piston reciprocable therein, a striking bar projecting from the pistonthrough one end of the cylinder,

and fluid distribution means for actuating said pistonincluding meansfor continuously admitting fluid pressure to the forward end of; thecylinder to act on the reduced area of the piston around the strikingbar, a valve for controlling the supply and exhaust of fluid'fromtherear end of the cylinder, said valve having a central spool foralternately establishing communication of the rear end of the cylinderwith the supply and exhaust, a larger spool on one side of said centralspool, said spoolspresenting a diflerential area to the action of fluidsupply pressure tending to holdthe valve. in one extreme position, a

throwing passage controlled by the piston for admitting pressure-fluidfrom the cylinder to the opposite side of said 1 r er spool for throwingthe valve to its other extreme position, and guiding means on saidvalvejon the opposite side of said central spool from the larger spool,said guiding meansconstituting a third spool of the same size as thecentral spool, anda'leak passage for relieving the throwing pressure onsaid larger spool when said throwing passage is closed to said cylinder.

7. In a drilling apparatus, a fluid pressure bar projecting from saidhead, and fluid distribution means for. effecting reciprocation of saidpiston including a valve having large and small spools, a fluid supplyinlet, a passage for conducting live fluid to the front end of saidpiston, a passage controlled by the smaller spool whereby live pressurefluid communicates with the rear end of said piston, an exhaust passage,a passage leading from said cylinder and controlled by said piston head,said piston controlled passage being adapted to have communication withsaid exhaust passage through said valve mechanism and to conduct livepressure fluid to one side of the larger spool to move said valve.

The combination set forth in claim 7 further characterized in that atransverse surface of said valveis constantly subjected to live fluidpressure.

9. The combination set forth in claim 7 further characterized in that atransverse surface of-said valve is constantly subjected to livepressure fluid, and means are provided whereby the actuating fluid fromone end of said cylinder is directed to said exhaust passage by thesmaller spool.

10. A pressi'n-e fluid motor comprising a cylinder, a pistonreciproc'able therein, and

fluid distributionmeans for efii'ecti n g reciprocation of said pistonincluding an inlet passage, a passage for admitting pressure fluid tothe front end of said piston from said inlet, means for controlling thesu ply of iiuid for and exhaust of fluid from the rear end of saidpiston comprising areciprocable differential fluid distribution valvehaving a large spool and a reduced spool, a passage controlled by saidpiston for admitting pressure fluid from said cylinder to one surface ofsaid large spool for throwing said valve in one direction and to connectthe rear end of said piston through the valve chest directly with therear end of said first mentioned passage, and a passage for constantlyadmit ting pressure fluid to the opposite surface of said large spoolfor throwing said valve in the opposite direction to connect the rearend of said piston with the exhaust.

llfA pressure fluid motor comprising a cylinder, a piston reciprocabletherein, and fluid distribution means for effecting reciprocation ofsaid piston including an inlet, means for controlling the supply andexhaust of fluid for the rear end of said piston comprising areciprocabl'e differential fluid distribution valve having a. largespool and a reduced spool, a'pa'ssa'ge controlled by said "piston foradmitting pressure fluid from said cylinder to one surface of send largespool for throwing said valve in one direction to connect one end. ofsaid piston with the fluid supply, a passage for constantly admittingpressure fluid to the opposite surface of said large spool to throw saidvalve in the opposite direction to connect the rear end of said pistonto the exhaust, and a leak passage for connecting the pressure area atthe rear end of said large spool with the exhaust.

In testimony whereof I afiix my signature.

ELMER G. GARTIN.

